Addressing the Labour Party Conference in Manchester today, Brown received cheers when he said he would offer nursery places for "every parent that wants one".
Currently parents can claim 12.5 free hours of nursery care each week for children aged three or four, but the PM has pledged to extend this to fifteen hours this autumn and lower the minimum age.
The announcement is expected to be the first of a raft of government family-friendly initiatives due over the coming months.
The Conservative party has tentatively approved of the pledge, but claims there has been no explanation of where the money will come from.
Shadow families minister Maria Miller said: "We fully support measures that will help improve access to affordable childcare, but nobody is helped by the Prime Minister making unfunded promises."
The announcement came as part of the keynote conference address that has been herlded as the speech that would 'make or break' the PM's leadership.
